<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        img{
            padding: 0;
            margin: 0;
        }
        .container{
            position:relative;
            width: 600px;
            height: 400px;
            margin: 0 auto;
            overflow: hidden;
        }
        .ul-img{
            position: absolute;
            display: flex;
            width: 4200px;
            height: 400px;
            left: 0;
            padding: 0;
            margin: 0;
        }
        .li-img{
            list-style: none;
            width: 600px;
            height: 400px;
            display: flex;
            align-items: center;
            justify-content: center;
            background-color: lightgreen;
            font-size: 30px;
            font-weight: 800;
            border: 1px solid #ccc;
            box-sizing: border-box;
        }
        /*上一张，下一张*/
        .prev,
        .next {
            position: absolute;
            height: 400px;
            width: 80px;
            display: flex;
            justify-content: center;
            align-items: center;
            top: 0;
        }

        .prev {
            left: 0;
        }

        .next {
            right: 0;
        }

        .prev span,
        .next span {
            display: block;
            color: #fff;
            width: 40px;
            height: 40px;
            display: flex;
            justify-content: center;
            align-items: center;
            background-color: rgba(0, 0, 0, 0.5);
            border-radius: 50%;
            cursor: pointer;
        }
        /* 数字切换按钮 */
        .num-box {
            position: absolute;
            left: 50%;
            bottom: 20px;
            transform: translate(-50%, 0);
            z-index: 2;
        }

        .num-ul {
            list-style: none;
            margin: 0;
            padding: 0;
            display: flex;
        }

        .num-ul li {
            height: 20px;
            width: 20px;
            border-radius: 50%;
            background-color: rgba(0, 0, 0, 0.5);
            display: flex;
            justify-content: center;
            align-items: center;
            font-size: 9px;
            color: #fff;
            margin: 0 4px;
            cursor: pointer;
            user-select: none;
        }
    </style>
</head>
<body>
    <div class="container">
    <!--图片列表-->
        <ul class="ul-img">
            <li class="li-img">
                <img src="/static/pic/背影.jpg" alt="图片加载失败！" style="width: 600px;height: 400px">
            </li>
            <li class="li-img">
                <img src="/static/pic/树干.jpg" alt="图片加载失败！" style="width: 600px;height: 400px">
            </li>
            <li class="li-img">
                <img src="/static/pic/甜点.jpg" alt="图片加载失败！" style="width: 600px;height: 400px">
            </li>
            <li class="li-img">
                <img src="/static/pic/屋顶.jpg" alt="图片加载失败！" style="width: 600px;height: 400px">
            </li>
            <li class="li-img">
                <img src="/static/pic/夜景.jpg" alt="图片加载失败！" style="width: 600px;height: 400px">
            </li>
        </ul>
    <!--上一张、下一张按钮-->
        <div class="prev">
            <span>&lt;</span>
        </div>
        <div class="next">
            <span>&gt;</span>
        </div>
    <!-- 数字切换按钮-->
        <div class="num-box">
            <ul class="num-ul">
                <li data-index="0">1</li>
                <li data-index="1">2</li>
                <li data-index="2">3</li>
                <li data-index="3">4</li>
                <li data-index="4">5</li>
            </ul>
        </div>
    </div>
</body>
<script>
    // 获取元素节点
    var containerDom = document.getElementsByClassName("container")[0]; // 容器
    var ulDom = document.getElementsByClassName("ul-img")[0]; // 图片盒子
    var prevDom = document.getElementsByClassName("prev")[0].firstElementChild; // 上一张按钮
    var nextDom = document.getElementsByClassName("next")[0].firstElementChild; // 下一张按钮
    var numUlDom = document.getElementsByClassName("num-ul")[0]; // 数字按钮父级容器
    var numList = document
        .getElementsByClassName("num-ul")[0]
        .getElementsByTagName("li"); // 数字切换按钮列表

    // 定义全局变量
    var currentIndex = 0; // 当前显示的图片索引
    var timer = null; // 自动播放定时器
    numList[currentIndex].style.backgroundColor = "#ccc"; // 默认选中第一个数字
    // 上一张
    prevDom.addEventListener("click", prevFun);
    // 下一张
    nextDom.addEventListener("click", nextFun);
    // 鼠标移入容器，停止自动播放
    containerDom.addEventListener("mouseenter", stopAutoPlay);
    // 鼠标移出容器，开启自动播放
    containerDom.addEventListener("mouseleave", autoPlay);
    // 数字按钮点击事件
    numUlDom.addEventListener("click", numClick);

    // 开启自动播放
    autoPlay();

    // 切换上一张
    function prevFun() {
        ulDom.style.transition = "0.5s";
        numList[currentIndex].style.backgroundColor = ""; // 清空上一个按钮的样式
        if (currentIndex === 0) {
            ulDom.style.transition = "0s"; // 为了实现无缝滚动，清除动画
            currentIndex = 4;
        } else {
            --currentIndex;
        }
        ulDom.style.left = `-${currentIndex * 600}px`;
        numList[currentIndex].style.backgroundColor = "#ccc";
    }

    // 切换下一张
    function nextFun() {
        ulDom.style.transition = "0.5s";
        numList[currentIndex].style.backgroundColor = ""; // 清空上一个按钮的样式
        if (currentIndex === 4) {
            ulDom.style.transition = "0s"; // 为了实现无缝滚动，清除动画
            currentIndex = 0; // 重新播放第一张
        } else {
            ++currentIndex;
        }
        ulDom.style.left = `-${currentIndex * 600}px`;
        numList[currentIndex].style.backgroundColor = "#ccc"; // 设置按钮选中样式
    }

    // 数字按钮点击事件
    function numClick(e) {
        ulDom.style.transition = "0.5s";
        let index = e.target.dataset.index;
        if (index == undefined) {
            return;
        }
        numList[currentIndex].style.backgroundColor = ""; // 清空上一个按钮的样式
        currentIndex = Number(index);
        numList[currentIndex].style.backgroundColor = "#ccc";
        ulDom.style.left = `-${currentIndex * 600}px`;
    }

    // 循环播放
    function autoPlay() {
        timer = setInterval(nextFun, 1000);
    }

    // 关闭自动播放
    function stopAutoPlay() {
        // 清除定时器
        clearInterval(timer);
    }

</script>
</html>